Process methods for phosphatidylinositol 3-kinase inhibitors

ABSTRACT

A process for the synthesis of quinazolinone containing compounds which may be useful for the treatment of cancer, is hereby disclosed. In addition, compound intermediates relating to these processes are also disclosed.

CROSS REFERENCE TO RELATED APPLICATION

This application claims the benefit of and priority to U.S. Provisional Application Ser. No. 61/919,548, filed Dec. 20, 2013, the disclosure of which is hereby incorporated by reference in its entirety.

BACKGROUND OF THE INVENTION

The present disclosure relates generally to the synthesis or preparation of certain phosphatidylinositol 3-kinase (PI3K) inhibitors and their synthetic intermediates. Inhibitors of PI3K, such as quinazoline-purinyl containing compounds, may be useful in treating PI3K-mediated disorders such as cancer. There is a need to have alternative processes in making such PI3K inhibitors.

BRIEF SUMMARY OF THE INVENTION

The present disclosure provides a process of making certain PI3K inhibitors and compound intermediates thereof.

In one embodiment, the application discloses processes for synthesizing a compound of formula

or a salt thereof.

In another embodiment, the application discloses processes for synthesizing a compound of formula II:

or a salt thereof.

In an alternative embodiment, the application discloses processes for synthesizing a compound of formula III:

or a salt thereof.

In one embodiment, the application discloses a process for synthesizing a compound of formula

or a salt thereof, comprising step a) combining a compound of formula 2:

or a salt thereof, and a compound of formula 3:

wherein the compound of formula 1 or a salt thereof is synthesized, wherein R¹ is halo; R² is selected from the group consisting of H and optionally substituted C₁-C₈ alkyl; and R³ and R⁴ are each independently selected from the group consisting of hydrogen, an amino protective group and an optionally substituted purinyl group.

In a further embodiment the process further comprises step b) combining the compound of formula 1 or a salt thereof; and

a compound of formula 22:

wherein n is 0-5; and each R⁵ is independently selected from the group consisting of alkyl, alkenyl, alkynyl, carboxy, carboxyalkyl, aminocarbonyl, hydroxy, alkoxy, halogen, CF₃, amino, substituted amino, nitro, thiol, cyano, cycloalkyl, heterocyclyl, aryl, and heteroaryl; and wherein a compound of formula 4:

or a salt thereof is synthesized.

In yet a further embodiment, the process further comprises step c) combining the compound of formula 4 or a salt thereof, wherein at least one of R₃ and R₄ of the compound of formula 4 is an amino protective group; and one or more reagents, wherein the one or more reagents are used to remove the amino protective group; wherein a compound of formula 5:

or a salt thereof is synthesized; step d) combining the compound of formula 5 or a salt thereof and a compound of formula 6:

wherein X is selected from the group consisting of halogen, mesyl, mesylate, tosyl and tosylate; and R⁶ is hydrogen or an amino protective group; wherein a compound of formula 7:

or a salt thereof is synthesized; and if R⁶ is an amino protective group, step e) further combining the compound of formula 7 or a salt thereof; and one or more reagents, wherein the one or more reagents are used to remove the amino protective group, wherein a compound of formula I:

or a salt thereof is synthesized.

In one embodiment, the present application discloses a process for synthesizing a compound of formula 8:

or a salt thereof, comprising step a) combining a compound of formula 9

or a salt thereof, and a compound of formula 10

wherein the compound of formula 8 or a salt thereof is synthesized.

In a further embodiment, the process further comprises step b) combining the compound of formula 8 or a salt thereof and aniline, wherein a compound of formula 11:

or a salt thereof is synthesized.

In yet a further embodiment, the process further comprises step c) combining the compound of formula 11 or a salt thereof and an acid, wherein a compound of formula 12:

or a salt thereof is synthesized; step d) combining the compound of formula 12 or a salt thereof and a compound of formula 13

wherein a compound of formula 14:

or a salt thereof is synthesized; and step e) combining the compound of formula 14 or a salt thereof and an acid, wherein a compound of formula II:

or a salt thereof is synthesized.

In an alternative embodiment, the application discloses a process for synthesizing a compound of formula 15:

or a salt thereof, comprising step a) combining a compound of formula 16:

or a salt thereof, and a compound of formula 10a:

wherein the compound of formula 15 or a salt thereof is synthesized.

In a further embodiment, the process further comprises step b) combining the compound of formula 15 or a salt thereof and aniline, wherein a compound of formula 17:

or a salt thereof is synthesized.

In yet a further embodiment, the process further comprises step c) combining the compound of formula 17 or a salt and an acid thereof, wherein a compound of formula 18:

or a salt thereof is synthesized; step d) combining the compound of formula 18 or a salt thereof and a compound of formula 13

wherein a compound of formula (19):

or a salt thereof is synthesized; and step e) combining the compound of formula 19 or a salt thereof and an acid, wherein the compound of formula III:

or a salt thereof is synthesized.

In some embodiments, the application discloses the intermediate compounds formed from the processes disclosed herein. In some embodiments, the application discloses compounds selected from the group consisting of

and salts thereof. In certain embodiments, compounds of formula (8), (15), (14), (19), (20), and (21), are disclosed. In certain embodiments, pharmaceutically acceptable salts of the compounds of formula (8), (15), (14), (19), (20), and (21), are disclosed.

DETAILED DESCRIPTION OF THE INVENTION Definitions

As used in the present specification, the following words and phrases are generally intended to have the meanings as set forth below, except to the extent that the context in which they are used indicates otherwise.

The term “about” includes and describes the value or parameter per se. For example, “about x” includes and describes “x” per se. In certain embodiment, the term “about” when used in association with a measurement, or used to modify a value, a unit, a constant, or a range of values, refers to variations of +/−1-10%. In some embodiments, the term “about” when used in association with a measurement, or used to modify a value, a unit, a constant, or a range of values, refers to variations of +/−5%. In some embodiments, the term “about” when used in association with a measurement, or used to modify a value, a unit, a constant, or a range of values, refers to variations of +/−10%.

The term “between” includes and describes the value or parameter per se. For example, “between x and y” includes and describes “x” and “y” per se.

The term “and/or” includes subject matter in the alternative as well as subject matter in combination. For instance, “x, and/or y”, includes “x or y” and “x and y”.

The term “alkyl” as used herein refers to a straight or branched chain, saturated hydrocarbon having the indicated number of carbon atoms. For example, (C₁-C₈)alkyl is meant to include, but is not limited to methyl, ethyl, propyl, isopropyl, butyl, sec-butyl, tert-butyl, pentyl, isopentyl, neopentyl, hexyl, isohexyl, and neohexyl. An alkyl group can be unsubstituted or optionally substituted with one or more substituents as described herein throughout.

The term “substituted alkyl” refers to: 1) an alkyl group as defined above, having 1, 2, 3, 4 or 5 substituents, (in some embodiments, 1, 2 or 3 substituents) selected from the group consisting of alkenyl, alkynyl, carboxy, carboxyalkyl, aminocarbonyl, hydroxy, alkoxy, halogen, CF₃, amino, substituted amino, nitro, thiol, cyano, cycloalkyl, heterocyclyl, aryl, and heteroaryl.

The term “alkylene” refers to a diradical of a branched or unbranched saturated hydrocarbon chain, in some embodiments, having from 1 to 20 carbon atoms (e.g. 1-10 carbon atoms or 1, 2, 3, 4, 5 or 6 carbon atoms). This term is exemplified by groups such as methylene(—CH₂—), ethylene (—CH₂CH₂—), the propylene isomers (e.g., —CH₂CH₂CH₂— and —CH(CH₃)CH₂—), and the like.

The term “substituted alkylene” refers to an alkylene group as defined above having 1 to 5 substituents (in some embodiments, 1, 2 or 3 substituents) as defined for substituted alkyl.

The term “aralkyl” refers to an aryl group covalently linked to an alkylene group, where aryl and alkylene are defined herein. “Optionally substituted aralkyl” refers to an optionally substituted aryl group covalently linked to an optionally substituted alkylene group. Such aralkyl groups are exemplified by benzyl, phenylethyl, 3-(4-methoxyphenyl)propyl, and the like.

The term “aralkyloxy” refers to the group —O-aralkyl. “Optionally substituted aralkyloxy” refers to an optionally substituted aralkyl group covalently linked to an optionally substituted alkylene group. Such aralkyl groups are exemplified by benzyloxy, phenylethyloxy, and the like.

The term “alkenyl” refers to a monoradical of a branched or unbranched unsaturated hydrocarbon group having from 2 to 20 carbon atoms (in some embodiments, from 2 to 10 carbon atoms, e.g. 2 to 6 carbon atoms) and having from 1 to 6 carbon-carbon double bonds, e.g. 1, 2 or 3 carbon-carbon double bonds. In some embodiments, alkenyl groups include ethenyl (or vinyl, i.e. —CH═CH₂), 1-propylene (or allyl, i.e. —CH₂CH═CH₂), isopropylene (—C(CH₃)═CH₂), and the like.

The term “substituted alkenyl” refers to an alkenyl group as defined above having 1 to 5 substituents (in some embodiments, 1, 2 or 3 substituents) as defined for substituted alkyl.

The term “alkynyl” refers to a monoradical of an unsaturated hydrocarbon, in some embodiments, having from 2 to 20 carbon atoms (in some embodiments, from 2 to 10 carbon atoms, e.g. 2 to 6 carbon atoms) and having from 1 to 6 carbon-carbon triple bonds e.g. 1, 2 or 3carbon-carbon triple bonds. In some embodiments, alkynyl groups include ethynyl (—C≡CH), propargyl (or propynyl, i.e. —C≡CCH₃), and the like.

The term “substituted alkynyl” refers to an alkynyl group as defined above having 1 to 5 substituents (in some embodiments, 1, 2 or 3 substituents) as defined for substituted alkyl.

The term “hydroxy” or “hydroxyl” refers to a group —OH.

The term “alkoxy” refers to the group R—O—, where R is alkyl; and includes, by way of example, methoxy, ethoxy, n-propoxy, iso-propoxy, n-butoxy, tert-butoxy, sec-butoxy, n-pentoxy, n-hexyloxy, 1,2-dimethylbutoxy, and the like.

The term “substituted alkoxy” refers to the group R—O—, where R is substituted alkyl, where substituted alkyl, substituted alkenyl and substituted alkynyl are as defined herein.

The term “cycloalkyl” refers to cyclic alkyl groups of from 3 to 20 carbon atoms having a single cyclic ring or multiple condensed rings. Such cycloalkyl groups include, by way of example, single ring structures such as cyclopropyl, cyclobutyl, cyclopentyl, cyclooctyl and the like or multiple ring structures such as adamantanyl and bicyclo[2.2.1]heptanyl or cyclic alkyl groups to which is fused an aryl group, for example indanyl, and the like, provided that the point of attachment is through the cyclic alkyl group.

The term “cycloalkenyl” refers to cyclic alkyl groups of from 3 to 20 carbon atoms having a single cyclic ring or multiple condensed rings and having at least one double bond and in some embodiments, from 1 to 2 double bonds.

The terms “substituted cycloalkyl” and “substituted cycloalkenyl” refer to cycloalkyl or cycloalkenyl groups having 1, 2, 3, 4 or 5 substituents (in some embodiments, 1, 2 or 3substituents), selected from the group consisting of alkyl, alkenyl, alkynyl, carboxy, carboxyalkyl, aminocarbonyl, hydroxy, alkoxy, halogen, CF₃, amino, substituted amino, nitro, thiol, cyano, cycloalkyl, heterocyclyl, aryl, and heteroaryl.

The term “aryl” refers to an aromatic carbocyclic group of 6 to 20 carbon atoms having a single ring (e.g., phenyl) or multiple rings (e.g., biphenyl) or multiple condensed (fused) rings (e.g., naphthyl, fluorenyl and anthryl). In some embodiments, aryls include phenyl, fluorenyl, naphthyl, anthryl, and the like.

Unless otherwise constrained by the definition for the aryl substituent, such aryl groups can optionally be substituted with 1, 2, 3, 4 or 5 substituents (in some embodiments, 1, 2 or 3substituents), selected from the group consisting of alkyl, alkenyl, alkynyl, carboxy, carboxyalkyl, aminocarbonyl, hydroxy, alkoxy, halogen, CF₃, amino, substituted amino, nitro, thiol, cyano, cycloalkyl, heterocyclyl, aryl, and heteroaryl.

The term “substituted purinyl” refers to a purinyl having 1, 2, 3, 4, or 5 substituents (in some embodiments 1, 2, or 3 substituents), each independently selected from the group consisting of alkyl, alkenyl, alkynyl, carboxy, carboxyalkyl, aminocarbonyl, hydroxy, alkoxy, halogen, CF₃, amino, substituted amino, nitro, thiol, cyano, cycloalkyl, heterocyclyl, aryl, and heteroaryl. In some embodiments, purinyl is substituted with 1, 2, or 3 substituents selected from the group consisting of methyl, ethyl, propyl, NH₂, and N(CH₃)₂.

The term “heterocyclyl,” “heterocycle,” or “heterocyclic” refers to a monoradical saturated group having a single ring or multiple condensed rings, having from 1 to 40 carbon atoms, and from 1 to 10 heteroatoms or 1 to 4 heteroatoms within the ring, each heteroatom independently selected from the group consisting of nitrogen, sulfur, phosphorus, and oxygen.

Unless otherwise constrained by the definition for the heterocyclic substituent, such heterocyclic groups can be optionally substituted with 1 to 5 substituents (in some embodiments, 1, 2 or 3 substituents), selected from the group consisting of alkyl, alkenyl, alkynyl, carboxy, carboxyalkyl, aminocarbonyl, hydroxy, alkoxy, halogen, CF₃, amino, substituted amino, nitro, thiol, cyano, cycloalkyl, heterocyclyl, aryl, and heteroaryl. Examples of heterocyclics include tetrahydrofuranyl, morpholino, piperidinyl, and the like.

The term “heteroaryl” refers to a group comprising single or multiple rings comprising 1 to 15 carbon atoms and 1 to 4 heteroatoms selected from oxygen, nitrogen and sulfur within at least one ring. The term “heteroaryl” is generic to the terms “aromatic heteroaryl” and “partially saturated heteroaryl”. The term “aromatic heteroaryl” refers to a heteroaryl in which at least one ring is aromatic, regardless of the point of attachment. Examples of aromatic heteroaryls include pyrrole, thiophene, pyridine, quinoline, pteridine. The term “partially saturated heteroaryl” refers to a heteroaryl having a structure equivalent to an underlying aromatic heteroaryl which has had one or more double bonds in an aromatic ring of the underlying aromatic heteroaryl saturated. Examples of partially saturated heteroaryls include dihydropyrrole, dihydropyridine, 2-oxo-1,2-dihydropyridin-4-yl, and the like.

Unless otherwise constrained by the definition for the heteroaryl substituent, such heteroaryl groups can be optionally substituted with 1 to 5 substituents (in some embodiments, 1, 2 or 3 substituents) selected from the group consisting alkyl, alkenyl, alkynyl, carboxy, carboxyalkyl, aminocarbonyl, hydroxy, alkoxy, halogen, CF₃, amino, substituted amino, nitro, thiol, cyano, cycloalkyl, heterocyclyl, aryl, and heteroaryl. Such heteroaryl groups can have a single ring (e.g., pyridyl or furyl) or multiple condensed rings (e.g., indolizinyl, benzothiazole or benzothienyl). Examples of nitrogen heterocyclyls and heteroaryls include, but are not limited to pyrrole, imidazole, pyrazole, pyridine, pyrazine, pyrimidine, pyridazine, indolizine, isoindole, indole, indazole, purine, quinolizine, isoquinoline, quinoline, phthalazine, naphthylpyridine, quinoxaline, quinazoline, cinnoline, pteridine, carbazole, carboline, phenanthridine, acridine, phenanthroline, isothiazole, phenazine, isoxazole, phenoxazine, phenothiazine, imidazolidine, imidazoline, and the like as well as N-alkoxy nitrogen containing heteroaryl compounds.

The term “substituted amino” refers to the group —NRR where each R is independently selected from the group consisting of hydrogen, alkyl, cycloalkyl, aryl, heteroaryl and heterocyclyl provided that both R groups are not hydrogen. Unless otherwise constrained by the definition, all substituents may optionally be further substituted by 1, 2 or 3 substituents chosen from alkyl, alkenyl, alkynyl, carboxy, carboxyalkyl, aminocarbonyl, hydroxy, alkoxy, halogen, CF₃, amino, substituted amino, nitro, thiol, cyano, cycloalkyl, heterocyclyl, aryl, and heteroaryl.

The term “carboxyalkyl” refers to the groups —C(O)O-alkyl or —C(O)O-cycloalkyl, where alkyl and cycloalkyl are as defined herein, and may be optionally further substituted by alkyl, alkenyl, alkynyl, carboxy, carboxyalkyl, aminocarbonyl, hydroxy, alkoxy, halogen, CF₃, amino, substituted amino, nitro, thiol, cyano, cycloalkyl, heterocyclyl, aryl, and heteroaryl.

The term “aminocarbonyl” refers to the group —C(O)NRR where each R is independently hydrogen, alkyl, cycloalkyl, aryl, heteroaryl, heterocyclyl or where both R groups are joined to form a heterocyclic group (e.g., morpholino). Unless otherwise constrained by the definition, all substituents may optionally be further substituted by 1, 2 or 3 substituents chosen from alkyl, alkenyl, alkynyl, carboxy, carboxyalkyl, aminocarbonyl, hydroxy, alkoxy, halogen, CF₃, amino, substituted amino, nitro, thiol, cyano, cycloalkyl, heterocyclyl, aryl, and heteroaryl.

The term “thiol” refers to the group —SH.

The term “halogen” or “halo” refers to fluoro, bromo, chloro and iodo.

“Optional” or “optionally” means that the subsequently described event or circumstance may or may not occur, and that the description includes instances where said event or circumstance occurs and instances in which it does not.

A “substituted” group includes embodiments in which a monoradical substituent is bound to a single atom of the substituted group (e.g. forming a branch), and also includes embodiments in which the substituent may be a diradical bridging group bound to two adjacent atoms of the substituted group, thereby forming a fused ring on the substituted group.

Where a given group (moiety) is described herein as being attached to a second group and the site of attachment is not explicit, the given group may be attached at any available site of the given group to any available site of the second group. For example, an “alkyl-substituted phenyl”, where the attachment sites are not explicit, may have any available site of the alkyl group attached to any available site of the phenyl group. In this regard, an “available site” is a site of the group at which a hydrogen of the group may be replaced with a substituent.

A compound of a given formula is intended to encompass the compounds of the disclosure, and the salts, esters, isomers, tautomers, solvates, isotopes, hydrates, and prodrugs of such compounds. Additionally, the compounds of the disclosure may possess one or more asymmetric centers, and can be produced as a racemic mixture or as individual enantiomers or diastereoisomers. The number of stereoisomers present in any given compound of a given formula depends upon the number of asymmetric centers present (there are 2″ stereoisomers possible where n is the number of asymmetric centers). The individual stereoisomers (including individual enantiomers and diastereoisomers) as well as racemic and non-racemic mixtures of stereoisomers are encompassed within the scope of the present disclosure, all of which are intended to be depicted by the structures of this specification unless otherwise specifically indicated. Compounds of the present disclosure include separable rotational isomers, or atropisomers.

“Isomers” are different compounds that have the same molecular formula. Isomers include stereoisomers, enantiomers and diastereomers.

“Stereoisomers” are isomers that differ only in the way the atoms are arranged in space.

“Enantiomers” are a pair of stereoisomers that are non-superimposable mirror images of each other. A 1:1 mixture of a pair of enantiomers is a “racemic” mixture. The term“(±)” is used to designate a racemic mixture where appropriate.

“Diastereoisomers” are stereoisomers that have at least two asymmetric atoms, but which are not mirror-images of each other.

The absolute stereochemistry is specified according to the Cahn Ingold Prelog R S system. When the compound is a pure enantiomer, the stereochemistry at each chiral carbon may be specified by either R or S. Resolved compounds whose absolute configuration is unknown are designated (+) or (−) depending on the direction (dextro- or laevorotary) that they rotate the plane of polarized light at the wavelength of the sodium D line.

“Tautomers” are structural isomers resulting from the migration of an atom or a functional group within the same organic molecule and lead to a change in one or more of its structural skeleton, electronic density distribution, and chemical properties. It is understood that compounds disclosed herein includes tautomeric forms although not necessarily explicitly shown. In one example, purine may be represented by any of the following tautomers:

Accordingly, a reference to any one of the purine tautomers includes the other tautomeric forms.

The term “amino protective group” is well understood by the person skilled in synthetic organic chemistry as a moiety that can be selectively installed onto and removed from a suitable amine functional group. Amino protective groups, and methods for using them, are described in the authoritative treatise on the subject, P. G. M. Wuts and T. W. Greene, Greene's Protective Groups in Organic Synthesis, 4th Edition (Wiley, 2006). In some embodiments, the amino protective group is selected from the group consisting of a carbamate, an amide, and a sulfonamide. In some embodiments, the amino protective group is a benzyl group, or a Schiff base.

Non-limiting examples of carbamate based amino protective groups include methyl carbamate, 9-fluoroenylmethyl carbamate (FMOC), 2,2,2-trichloroethyl carbamate, 2-trimethylsilylethyl carbamate, 1,1-dimethylpropynyl carbamate, 1-methyl-1-phenethyl carbamate, 1-methyl-1-(4-biphenylyl)ethyl carbamate, 1,1-dimethyl-2-haloethyl carbamate, 1,1-dimethyl-2-cyanoethyl carbamate, t-butyl carbamate, cyclobutyl carbamate, 1-methylcyclobutyl carbamate, 1-adamantyl carbamate, vinyl carbamate, allyl carbamate, cinnamyl carbamate, 8-quinolyl carbamate, N-hydroxypiperidinyl carbamate, 4,5-diphenyl-3-oxazolin-2-one, benzyl carbamate, p-nitrobenzyl carbamate, 3,4-dimethoxy-6-nitrobenzyl carbamate, 2,4-dichlorobenzyl carbamate, 5-benzisoxazolylmethyl carbamate, 9-anthrylmethyl carbamate, diphenylmethyl carbamate, isonicotinyl carbamate, and S-benzyl carbamate, N—(N′-phenylaminothiocarbonyl) derivative. In one embodiment, the amino protective group is selected from the group consisting methyl carbamate, t-butyl carbamate, vinyl carbamate, and allyl carbamate. In another embodiment, the amino protective group is selected from the group consisting of t-butyl carbamate (BOC) and 9-fluoroenylmethyl carbamate (FMOC).

Non-limiting examples of amide based amino protective groups include N-formyl, N-acetyl, N-chloracetyl, N-trichloroacetyl, N-trifluoroacetyl, N-o-nitrophenylacetyl, N-o-nitrophoxyacetyl, N-acetoacetyl, N-3-phenylpropionyl, N-3-(p-hydroxyphenyl)propionyl, N-2-methyl-2-(o-nitrophenoxy)propionyl, N-4-chorobutyryl, N-o-nitrocinnamoyl, N-picolinoyl, N—(N′-acetylmethionyl), N-benzoyl, N-phthaloyl, and N-dithiasuccinoyl. In one embodiment, the amino protective group is selected from the group consisting of N-formyl, N-acetyl, N-chloracetyl, N-trichloroacetyl, N-trifluoroacetyl, and N-acetoacetyl.

Other non-limiting examples of amino protective groups include N-allyl, N-phenacyl, N-3-acetoxypropyl, quaternary ammonium salts, N-methyoxymethyl, N-benzyloxymethyl, N-pivaloyloxymethyl, N-tetrahydropyranyl, N-2,4-dinitrophenyl, N-benzyl, N-o-nitrobenzyl, N-di(p-methoxyphenyl)methyl, N-triphenylmethyl, N-(p-methyoxyphenyl)diphenylmethyl, N-diphenyl-4-pyridylmethyl, N-2-picolyl N′-oxide, N,N′-isopropylidene, N-salicylidene, N-(5,-dimethyl-3-oxo-1-cyclohexenyl), N-nitro, N-oxide, N-diphenylphosphinyl, N-dimetylthiophosphinyl, N-dimethylthiophosphinyl, N-benzenesulfenyl, N-o-nitrobenzenesulfenyl, N-2,4,6-trimethylbenzenesulfonyl, N-toluenesulfonyl, N-benzylsulfonyl, N-trifluoromethylsulfonyl, and N-phenyacylsulfonyl. In one embodiment, the amino protective group is selected from the group consisting of N-allyl, N-phenacyl, N-3-acetoxypropyl, quaternary ammonium salts, N-methyoxymethyl, N-benzyloxymethyl, N-pivaloyloxymethyl, and N-tetrahydropyranyl. In one embodiment, the amino protective group is N-tetrahydropyranyl.

If there is a discrepancy between a depicted structure and a name given to that structure, the depicted structure controls. In addition, if the stereochemistry of a structure or a portion of a structure is not indicated with, for example, bold, wedged, or dashed lines, the structure or portion of the structure is to be interpreted as encompassing all stereo isomers of it.

The term “solvate” refers to a complex formed by the combining of a compound of any formula as disclosed herein, and a solvent.

The term “hydrate” refers to the complex formed by the combining of a compound of any formula disclosed herein, and water.

Any formula or structure given herein is also intended to represent unlabeled forms as well as isotopically labeled forms of the compounds. Isotopically labeled compounds have structures depicted by the formulas given herein except that one or more atoms are replaced by an atom having a selected atomic mass or mass number. Examples of isotopes that can be incorporated into compounds of the disclosure include isotopes of hydrogen, carbon, nitrogen, oxygen, phosphorous, fluorine and chlorine, such as, but not limited to ²H (deuterium, D), ³H (tritium), ¹¹C, ¹³C, ¹⁴C, ¹⁴C, ¹⁵N, ¹⁸F, ³¹P, ³²P, ³⁵S, ³⁶Cl and ¹²⁵I. Various isotopically labeled compounds of the present disclosure, for example those into which radioactive isotopes such as ³H, ¹³C and ¹⁴C are incorporated. Such isotopically labeled compounds may be useful in metabolic studies, reaction kinetic studies, detection or imaging techniques, such as positron emission tomography (PET) or single-photon emission computed tomography (SPECT) including drug or substrate tissue distribution assays or in radioactive treatment of patients.

In certain embodiments, the isotopically labeled compound is a compound of formula 6. In other embodiments, the isotopically labeled compound is a compound of formula 6, wherein X is a halogen and R⁶ is an amino protective group. In another embodiment, the isotopically labeled compound is a compound of formula 6, wherein X is CI and R⁶ is THF or THP.

The disclosure also includes compounds of any formula disclosed herein, in which from 1 to “n” hydrogens attached to a carbon atom is/are replaced by deuterium, in which n is the number of hydrogens in the molecule. Such compounds may exhibit increased resistance to metabolism and may thus be useful for increasing the half-life of a compound of any formula described herein, for instance formula II or formula III, when administered to a mammal. See, for example, Foster, “Deuterium Isotope Effects in Studies of Drug Metabolism”, Trends Pharmacal. Sci. 5(12):524-527 (1984). Such compounds are synthesized by means well known in the art, for example by employing starting materials in which one or more hydrogen atoms have been replaced by deuterium.

Deuterium labeled or substituted therapeutic compounds of the disclosure may have improved DMPK (drug metabolism and pharmacokinetics) properties, relating to distribution, metabolism and excretion (ADME). Substitution with heavier isotopes such as deuterium may afford certain therapeutic advantages resulting from greater metabolic stability, for example increased in vivo half-life or reduced dosage requirements. An ¹⁸F labeled compound may be useful for PET or SPECT studies. Isotopically labeled compounds of this disclosure and prodrugs thereof can generally be prepared by carrying out the procedures disclosed in the schemes or in the examples and preparations described below by substituting a readily available isotopically labeled reagent for a non-isotopically labeled reagent. Further, substitution with heavier isotopes, particularly deuterium (i.e., ²H or D) may afford certain therapeutic advantages resulting from greater metabolic stability, for example increased in vivo half-life or reduced dosage requirements or an improvement in therapeutic index. It is understood that deuterium in this context is regarded as a substituent in a compound of any formula disclosed herein. Similarly, in certain embodiments, tritium (i.e., ³H) is also regarded as a substituent in a compound of any formula disclosed herein. In certain embodiments, ¹⁴C is regarded as a substituent in a compound of any formula disclosed herein.

The concentration of such a heavier isotope, specifically deuterium, may be defined by an isotopic enrichment factor. In the compounds of this disclosure any atom not specifically designated as a particular isotope is meant to represent any stable isotope of that atom. Unless otherwise stated, when a position is designated specifically as “H” or “hydrogen”, the position is understood to have hydrogen at its natural abundance isotopic composition. Accordingly, in the compounds of this disclosure any atom specifically designated as a deuterium (D) is meant to represent deuterium.

In many cases, the compounds of this disclosure are capable of forming acid and/or base salts by virtue of the presence of amino and/or carboxyl groups or groups similar thereto.

Base addition salts can be prepared from inorganic and organic bases. Salts derived from in organic bases include, by way of example only, sodium, potassium, lithium, ammonium, calcium and magnesium salts. Further salts derived from organic bases include, but are not limited to, salts of primary, secondary and tertiary amines, such as alkyl amines, dialkyl amines, trialkylamines, substituted alkyl amines, di(substituted alkyl) amines, tri(substituted alkyl) amines, alkenyl amines, dialkenyl amines, trialkenyl amines, substituted alkenyl amines, di(substituted alkenyl) amines, tri(substituted alkenyl) amines, cycloalkyl amines, di(cycloalkyl) amines, tri(cycloalkyl) amines, substituted cycloalkyl amines, disubstituted cycloalkyl amine, trisubstituted cycloalkyl amines, cycloalkenyl amines, di(cycloalkenyl) amines, tri(cycloalkenyl)amines, substituted cycloalkenyl amines, disubstituted cycloalkenyl amine, trisubstituted cycloalkenyl amines, aryl amines, diaryl amines, triaryl amines, heteroaryl amines, diheteroarylamines, triheteroaryl amines, heterocyclic amines, diheterocyclic amines, triheterocyclic amines, mixed di- and tri-amines where at least two of the substituents on the amine are different and are selected from the group consisting of alkyl, substituted alkyl, alkenyl, substituted alkenyl, cycloalkyl, substituted cycloalkyl, cycloalkenyl, substituted cycloalkenyl, aryl, heteroaryl, heterocyclic, and the like. Also included are amines where the two or three substituents, together with the amino nitrogen, form a heterocyclic or heteroaryl group. In the general structure N(R^(x))(R^(y))(R^(z)), mono-substituted amines have 2 of the three substituents on nitrogen (R^(x), R^(y) and R^(z)) as hydrogen; di-substituted amines have 1 of the three substituents on nitrogen (R^(x), R^(y) and R^(z)) as hydrogen; and tri-substituted amines have none of the three substituents on nitrogen (R^(x), R^(y) and R^(z)) as hydrogen. R^(x), R^(y) and R^(z)may be selected from a variety of substituents such as hydrogen, optionally substituted alkyl, aryl, heteroaryl, cycloalkyl, cycloalkenyl, heterocyclyl and the like. The abovementioned amines refer to the compounds wherein either one, two or three substituents on the nitrogen are as listed in the name. For example, the term “cycloalkenyl amine” refers to cycloalkenyl-NH₂, wherein “cycloalkenyl” is as defined herein. The term “diheteroarylamine” refers to NH(heteroaryl)₂, wherein “heteroaryl” is as defined herein and so on.

Acid addition salts may be prepared from inorganic and organic acids. Acid addition salts may be prepared from inorganic acids such as hydrochloric acid, hydrobromic acid, sulfuric acid, nitric acid, phosphoric acid, and the like. Salts derived from organic acids include acetic acid, propionic acid, glycolic acid, pyruvic acid, oxalic acid, malic acid, malonic acid, succinic acid, maleic acid, fumaric acid, tartaric acid, citric acid, benzoic acid, cinnamic acid, mandelic acid, methanesulfonic acid, ethanesulfonic acid, p-toluene-sulfonic acid, salicylic acid, and the like.

In some embodiments, a salt is a “pharmaceutically acceptable salt”. A pharmaceutically acceptable salt of a given compound, for instance a compound of Formula I, II, or III, refers to salts that retain the biological effectiveness and properties of a given compound, and which are not biologically or otherwise undesirable. See: P. Heinrich Stahl and Camille G. Wermuth (Eds.) Pharmaceutical Salts: Properties, Selection, and Use (International Union of Pure and Applied Chemistry), Wiley-VCH; 2^(nd) revise Edition (May 16, 2011). In certain embodiments, a pharmaceutically acceptable salt of a given compound, for instance a compound of any of Formula I, II, or III, or a compound of any of formula 1-21, refers to that a salt form which is generally regarded as safe and suitable for use without undue toxicity, irritation, allergic response, and the like, commensurate with a reasonable benefit/risk ratio. Exemplary pharmaceutically acceptable salts include acid addition salts formed with inorganic acids such as hydrochloric acid, hydrobromic acid, sulfuric acid, nitric acid, phosphoric acid, and the like; or formed with organic acids such as acetic acid, benzenesulfonic acid, benzoic acid, camphorsulfonic acid, citric acid, ethanesulfonic acid, fumaric acid, glucoheptonic acid, gluconic acid, lactic acid, maleic acid, malonic acid, mandelic acid, methanesulfonic acid, 2-napththalenesulfonic acid, oleic acid, palmitic acid, propionic acid, stearic acid, succinic acid, tartaric acid, p-toluenesulfonic acid, trimethylacetic acid, and the like, and salts formed when an acidic proton present in the parent compound is replaced by either a metal ion, e.g., an alkali metal ion, an alkaline earth ion, or an aluminum ion; or coordinates with an organic base such as diethanolamine, triethanolamine, N-methylglucamine and the like. Also included in this definition are ammonium and substituted or quaternized ammonium salts. Representative non-limiting lists of pharmaceutically acceptable salts can be found in S. M. Berge et al., J. Pharma Sci., 66(1), 1-19 (1977), and Remington: The Science and Practice of Pharmacy, R. Hendrickson, ed., 21st edition, Lippincott, Williams & Wilkins, Philadelphia, Pa., (2005), at p. 732, Table 38-5, both of which are hereby incorporated by reference herein.

Compounds described herein may be presented in the form of chemical structures or names. The compounds shown below in Table A are named using ChemBioDraw Ultra 12.0 and it should be understood that other names may be used to identify compounds of the same structure. Other compounds or radicals may be named with common names, or systematic or non-systematic names. The compounds may also be named using other nomenclature systems and symbols that are commonly recognized in the art of chemistry including, for example, Chemical Abstract Service (CAS) and International Union of Pure and Applied Chemistry (IUPAC). The naming and numbering of the compounds of the present disclosure is illustrated with the compounds shown in Table A below.

TABLE A

(8)

(9)

(10)

(11)

(12)

(14)

(II)

(15)

(16)

(10a)

(17)

(18)

(19)

(III)

Processes

In some embodiments, the application discloses a process for synthesizing a compound of formula 1:

or a salt thereof, comprising step a) combining a compound of formula 2:

or a salt thereof, and a compound of formula 3:

wherein the compound of formula 1 or a salt thereof is synthesized, wherein R¹ is halo; R² is selected from the group consisting of H, and optionally substituted C₁-C₈ alkyl; and R³ and R⁴ are each independently selected from the group consisting of hydrogen, an amino protective group and an optionally substituted purinyl group.

In some embodiments, the application discloses a process for synthesizing a compound of formula 1:

comprising step a) combining a compound of formula 2:

and a compound of formula 3:

wherein the compound of formula 1 is synthesized, wherein R¹ is halo; R² is selected from the group consisting of H, and optionally substituted C₁-C₈ alkyl; and R³ and R⁴ are each independently selected from the group consisting of hydrogen, an amino protective group and an optionally substituted purinyl group.

In some embodiments, R¹ is F or Cl. In some embodiments, R¹ is F. In some embodiments, R² is selected from the group consisting of methyl, ethyl or propyl. In some embodiments, R² is ethyl. In some embodiments, R² is unsubstituted C₁-C₈ alkyl. In some embodiments, R² is unsubstituted. In some embodiments, R³ is H and R⁴ is an amino protective group. In some embodiments, R³ is H and R⁴ is a carbamate. In some embodiments, R³ is H and R⁴ is an optionally substituted purinyl group. In some embodiments, R¹ is F or Cl; R² is selected from the group consisting of methyl, ethyl or propyl; R³ is H and R⁴ is an amino protective group. In some embodiments, R¹ is F or Cl; R² is selected from the group consisting of methyl, ethyl or propyl; R³ is H and R⁴ is an optionally substituted purinyl group. In some embodiments, the amino protective group is selected from the group consisting of t-butyl carbamate, tetrahydropyranyl, alkylsilyl, benzyl, an optionally substituted purinyl group, and alkoxymethyl. In other embodiments, the amino protective group is carbamate. In some embodiments, the amino protective group is t-butyl carbamate (BOC) or 9-fluoroenylmethyl carbamate (FMOC). In some embodiments, the amino protective group is BOC. In some embodiments, when R⁴ is purinyl, the purinyl group has 0, 1, 2, 3, 4, or 5 substituents, each independently selected from the group consisting of alkyl, alkenyl, alkynyl, carboxy, carboxyalkyl, aminocarbonyl, hydroxy, alkoxy, halogen, CF₃, amino, substituted amino, nitro, thiol, cyano, cycloalkyl, heterocyclyl, aryl, and heteroaryl. In some embodiments, the purinyl group has 0, 1, 2, or 3 of the above list of substituents. In some embodiments, the purinyl group has 0, 1, 2, or 3 substituents selected from the group consisting of methyl, ethyl, propyl, NH₂, and N(CH₃)₂. In some embodiments, the purinyl group is has with 0, 1 or 2 substituents selected from the group consisting of methyl, ethyl, propyl, NH₂, and N(CH₃)₂. In some embodiments, the purinyl group has 1 substituent selected from the group consisting of methyl, ethyl, propyl, NH₂, and N(CH₃)₂. In some embodiments, the purinyl group is unsubstituted.

In some embodiments, step a) further comprises a step of combining a dehydrating agent. In some embodiments, step a) (i.e., combining a compound of formula 2 or a salt thereof and a compound of formula 3 or a salt thereof) is performed in the presence of a dehydrating agent. Non-limiting examples of the dehydrating agent include DPP (diphenylphosphite), TPP (triphenylphosphite), DCC (N,N′-dicyclohexylcarbodiimide), EDC (N-(3-dimethylaminopropyl)-N′-ethylcarbodiimide hydrochloride), and CDI (1,1′-carbonyldiimidazole). In some embodiments, the dehydrating agent is DPP (diphenylphosphite), TPP (triphenylphosphite), DCC (N,N′-dicyclohexylcarbodiimide), EDC (N-(3-dimethylaminopropyl)-N′-ethylcarbodiimide hydrochloride), CDI (1,1′-carbonyldiimidazole), or a mixture thereof. In some embodiments, the dehydrating agent is DPP. In some embodiments, step a) further comprises combining DPP. In some embodiments, step a) is performed in the presence of DPP.

In some embodiments, the dehydrating reagent is combined with a compound of formula 2 and a compound of formula 3, wherein the amount of the dehydrating reagent is in at least 2, 2.5, 3, 3.5, or 4 molar equivalents with respect to a compound of formula 2. In one embodiment, at least 2 molar equivalents of the dehydrating reagent with respect to the compound of formula 2 is combined with the compound of formula 2 and a compound of formula 3. In a another embodiment, at least 2 molar equivalents of the DPP (diphenylphosphite) with respect to the compound of formula 2 is combined with the compound of formula 2 and a compound of formula 3. In a yet another embodiment, at least 2 molar equivalents of the DPP (diphenylphosphite) with respect to the compound of formula 9 is combined with the compound of formula 9 and a compound of formula 10. In a further embodiment, at least 2 molar equivalents of the DPP (diphenylphosphite) with respect to the compound of formula 16 is combined with the compound of formula 16 and a compound of formula 10a.

In some embodiments, step a) further comprises a step of combining a base. In some embodiments, step a) (i.e., combining a compound of formula 2 or a salt thereof and a compound of formula 3 or a salt thereof) is performed in the presence of a base. Non-limiting examples of the base includes pyridine, 4-dimethylaminopyridine, triethylamine, isopropylethylamine, imidazole, DABCO, DBU, 2,6-lutidine, and N,N-diisopropylethylamine. In some embodiments, the base is pyridine, 4-dimethylaminopyridine, triethylamine, isopropylethylamine, imidazole, DABCO, DBU, 2,6-lutidine, N,N-diisopropylethylamine, or a mixture thereof. In some embodiments, the base is pyridine.

In some embodiments, step a) further comprises a solvent selected from the group consisting of pyridine, toluene, tetrahydrofuran, acetonitrile and 2-MeTHF. In some embodiments, step a) further comprises a solvent selected from the group consisting of pyridine, toluene, tetrahydrofuran, acetonitrile, 2-MeTHF, and a mixture thereof.

In some embodiments, step a) includes combining a compound of formula 2 or a salt thereof and a compound of formula 3 or a salt thereof with a dehydrating agent, a base, a solvent, or a mixture thereof. In some embodiments, step a) includes combining a compound of formula 2 or a salt thereof and a compound of formula 3 or a salt thereof with a dehydrating agent. In some embodiments, step a) includes combining a compound of formula 2 or a salt thereof and a compound of formula 3 or a salt thereof with a dehydrating agent and a base. In some embodiments, step a) includes combining a compound of formula 2 or a salt thereof and a compound of formula 3 or a salt thereof with a dehydrating agent, a base, and a solvent.

In some embodiments, step a) is performed at a temperature between 0 and 45 degrees Celsius, between 15 and 40 degrees Celsius, or between 20 and 30 degrees Celsius. In some embodiments, step a) is performed at a temperature below 45 degrees Celsius.

In some embodiments, the process further comprises step b) combining the compound of formula 1 or a salt thereof and

a compound of formula 22:

wherein n is 0-5; and each R⁵ is independently selected from the group consisting of alkyl, alkenyl, alkynyl, carboxy, carboxyalkyl, aminocarbonyl, hydroxy, alkoxy, halogen, CF₃, amino, substituted amino, nitro, thiol, cyano, cycloalkyl, heterocyclyl, aryl, and heteroaryl; and wherein a compound of formula 4:

or a salt thereof is synthesized.

In some embodiments, the process further comprises step b) combining the compound of formula 1; and a compound of formula 22:

wherein n is 0-5; and each R⁵ is independently selected from the group consisting of alkyl, alkenyl, alkynyl, carboxy, carboxyalkyl, aminocarbonyl, hydroxy, alkoxy, halogen, CF₃, amino, substituted amino, nitro, thiol, cyano, cycloalkyl, heterocyclyl, aryl, and heteroaryl; and wherein a compound of formula 4:

is synthesized.

In some embodiments, the compound of formula 22 is a substituted aniline. In some embodiments n is 1-5, and in other embodiments, n is 1-3. In some embodiments n is 0-3. In some embodiments n is 0, 1, or 2. In some embodiments n is 0. In some embodiments, each R⁵ is independently selected from the group consisting of alkyl, alkenyl, alkynyl, carboxy, carboxyalkyl, aminocarbonyl, hydroxy, alkoxy, halogen, CF₃, amino, substituted amino, nitro, thiol, cyano, cycloalkyl, heterocyclyl, aryl, and heteroaryl. In some embodiments, each R⁵ is independently C₁-C₄-alkyl or halo. In other embodiments, n is 1, 2, or 3; and R⁵ is selected from a group consisting of alkyl and halo. In some embodiments, n is 1, 2, or 3; and each R⁵ is independently selected from a group consisting of C₁-C₄-alkyl or halo. In yet other embodiments, n is 1, 2, or 3; and R⁵ is selected from a group consisting of methyl, F, and Cl. In some embodiments, n is 1, 2, or 3; and each R⁵ is independently selected from a group consisting of methyl, F, and Cl. In some embodiments, the compound of formula 22 is 2,6-difluoroaniline.

In some embodiments, step b) is performed at a temperature between 0 and 80 degrees Celsius; between 20 and 70 degrees Celsius; between 40 and 60 degrees Celsius; or between 45 and 55 degrees Celsius.

In some embodiments, the process further comprises step c) combining the compound of formula 4 or a salt thereof, wherein at least one of R₃ and R₄ of the compound of formula 4 is an amino protective group; and

one or more reagents, wherein the one or more reagents are used to remove the amino protective group; wherein a compound of formula 5:

or a salt thereof is synthesized.

In some embodiments, the process further comprises step c) combining the compound of formula 4, wherein at least one of R₃ and R₄ of the compound of formula 4 is an amino protective group; and

one or more reagents, wherein the one or more reagents are used to remove the amino protective group; wherein a compound of formula 5:

or a salt thereof is synthesized.

In some embodiments, the process further comprises step c) combining the compound of formula 4, wherein at least one of R₃ and R₄ of the compound of formula 4 is an amino protective group; and

two or more reagents, wherein one of the one or more reagents is used to remove the amino protective group and wherein another of the one or more reagents is an acid; wherein a compound of formula 5:

or a salt thereof is synthesized.

In some embodiments, the acid is hydrochloric acid.

In some embodiments, the process further comprises step d) combining the compound of formula 5 or a salt thereof and a compound of formula 6:

wherein X is selected from the group consisting of halogen, mesyl, mesylate, tosyl and tosylate; and R⁶ is hydrogen or an amino protective group; wherein a compound of formula 7:

or a salt thereof is synthesized.

In some embodiments, the process further comprises step d) combining the compound of formula 5 or a salt thereof and a compound of formula 6:

wherein X is selected from the group consisting of halogen, mesyl, mesylate, tosyl and tosylate; and R⁶ is hydrogen or an amino protective group; wherein a compound of formula 7:

is synthesized.

In some embodiments, the process further comprises step c) combining the compound of formula 4 or a salt thereof, wherein at least one of R₃ and R₄ of the compound of formula 4 is an amino protective group; and

one or more reagents, wherein the one or more reagents are used to remove the amino protective group; wherein a compound of formula 5:

or a salt thereof is synthesized; and step d) combining the compound of formula 5 or a salt thereof and a compound of formula 6:

wherein X is selected from the group consisting of halogen, mesyl, mesylate, tosyl and tosylate; and R⁶ is hydrogen or an amino protective group; wherein a compound of formula 7:

or a salt thereof is synthesized.

In some embodiments, the process further comprises step c) combining the compound of formula 4, wherein at least one of R₃ and R₄ of the compound of formula 4 is an amino protective group; and

one or more reagents, wherein the one or more reagents are used to remove the amino protective group; wherein a compound of formula 5:

or a salt thereof is synthesized; and step d) combining the compound of formula 5 or a salt thereof and a compound of formula 6:

wherein X is selected from the group consisting of halogen, mesyl, mesylate, tosyl and tosylate; and R⁶ is hydrogen or an amino protective group; wherein a compound of formula 7:

is synthesized.

In some embodiments, the compound of formula (5) is a salt. In some embodiments, the compound of formula (5) is an HCl salt.

In some embodiments, the compound of formula (7) is a salt. In some embodiments, the compound of formula (7) is an HCl salt.

In some embodiments, X is halogen. In other embodiments, X is Cl or Br. In other embodiments, X is Cl.

In some embodiments, step c) further comprises combining a solvent selected from the group consisting of acetonitrile, methanol, ethanol, isopropanol, n-propanol THF, water, and toluene. In some embodiments, step c) is performed in the presence of a solvent selected from the group consisting of acetonitrile, methanol, ethanol, isopropanol, n-propanol THF, water, toluene and mixtures thereof.

In some embodiments, step c) comprises combining one or more reagents for the deprotection of amino protective groups. For instance, if the amino protective group is an alkoxymethyl or a carbamate, such as a t-butyl carbamate or Fmoc, then the one or more reagents is an acid. In further embodiments, the acid is a mineral acid. Non-limiting examples of mineral acids include hydrochloric acid (HCl), nitric acid (HNO₃), phosphoric acid (H₃PO₄), sulfuric acid (H₂SO₄), boric acid (H₃BO₃), hydrofluoric acid (HF), hydrobromic acid (HBr), and perchloric acid (HClO₄). In some embodiments, the reagent is hydrochloric acid (HCl), nitric acid (HNO₃), phosphoric acid (H₃PO₄), sulfuric acid (H₂SO₄), boric acid (H₃BO₃), hydrofluoric acid (HF), hydrobromic acid (HBr), perchloric acid (HClO₄), or a mixture thereof. In other embodiments, the acid is trifluoroacetic acid (TFA). In another example, if the amino protective group is an alkyl silyl group, the one or more reagents are tetra-n-butylammonium fluoride (TBAF) and/or trifluoroacetic acid (TFA). In yet another example, if the amino protective group is benzyl, then the one or more reagents are Pd/C and H₂.

In some embodiments, step c) is performed at a temperature between 0 and 70 degrees Celsius; between 20 and 60 degrees Celsius; or between 35 and 50 degrees Celsius.

In some embodiments, the compound of formula 5 is synthesized as the free base, whereas in other embodiments, the compound of formula 5 is synthesized as a salt. In one embodiment, the compound of formula 5 is the salt of the compound of formula 12. In another embodiment, the compound of formula 12 is synthesized as the HCl salt. In yet other embodiments, the compound of formula 12 is synthesized as free base. In additional embodiments, the compound of formula 5 is the free base of the compound of formula 18. In some other embodiments, the compound of formula 5 is the salt of the compound of formula 18. By way of example, preparation of the salt can be followed by a neutralization step to synthesize the free base.

The choice of synthesizing either a salt or free base form may depend on the materials physical properties. In one embodiment, for stability reasons and manufacturing reasons, such as ease of handling, the compound of formula 12 is synthesized and/or isolated as the salt. In another example, the compound of formula 18 is synthesized and/or isolated as the free base, which is sufficiently stable and easy to handle.

In some embodiments, the compound of formula 5 or a salt thereof is crystallized from one or more solvents independently selected from the group comprising water, methanol, ethanol, isopropanol, n-propanol, concentrated NH₄OH, acetonitrile, MTBE (tert-butyl methyl ether), DCM (dichloromethane), EtOAc (ethyl acetate), iPrOAc (isopropylacetate), toluene, 2-Me-THF, DIPE (diisopropylether), heptane and heptanes. In some embodiments, the compound of formula 5 or a salt thereof is crystallized from one or more solvents selected from the group consisting of water, NH₄OH, acetonitrile, isopropanol, toluene, and mixtures thereof. In one embodiment, the one or more solvents are i) water, NH₄OH, and acetonitrile; or ii) isopropanol and toluene.

In some embodiments, step d) comprises a step of combining a base selected from the group consisting of triethylamine, pyridine, Hunig's base, and a carbonate base. In some embodiments, step d) comprises a step of combining a base selected from the group consisting of triethylamine, pyridine, Hunig's base, a carbonate base, and combinations thereof.

In some embodiments, step d) further comprises combining a solvent selected from the group consisting of water, an alcoholic solvent, and combinations thereof.

In some embodiments, step d) includes combining the compound of formula 5 or a salt thereof and a compound of formula 6 with a base or a solvent. In some embodiments, step d) includes combining the compound of formula 5 or a salt thereof and a compound of formula 6 with a base. In some embodiments, step d) includes combining the compound of formula 5 or a salt thereof and a compound of formula 6 with a solvent. In some embodiments, step d) includes combining the compound of formula 5 or a salt thereof and a compound of formula 6 with a base and a solvent.

In some embodiments, step d) is performed at a temperature between 35 and 110 degrees Celsius; between 40 and 90 degrees Celsius; between 50 and 80 degrees Celsius; or between 60 and 90 degrees Celsius.

In some embodiments, the compound of formula 7 or a salt thereof is crystallized from one or more solvents selected from the group consisting of alcohol and water. In other embodiments, the one or more solvents are i) methanol and water; ii) ethanol and water; iii) propanol and water; or iv) isopropanol and water.

In some embodiments, the compound of formula 6 is an unprotected purinyl compound, wherein R⁶ is hydrogen. In alternative embodiments, the compound of formula 6 is a protected purinyl compound wherein R⁶ is an amino protecting group. Use of the protected purinyl compound, such as the compound of formula 13, to synthesize a compound of formula 7 or a salt thereof has been observed to proceed faster, with less dipurine adducts, and at a higher yield compared to use of an unprotected purinyl compound.

In one embodiment, if R⁶ is an amino protective group, the process further comprises step e) combining the compound of formula 7, or a salt thereof, and

one or more reagents, wherein the one or more reagents are used to remove the amino protective group, wherein a compound of formula I:

or a salt thereof is synthesized. In one embodiment, R⁶ is an amino protective group.

In one embodiment, if R⁶ is an amino protective group, the process further comprises step e) combining the compound of formula 7, or a salt thereof, and

one or more reagents, wherein the one or more reagents are used to remove the amino protective group, wherein a compound of formula I:

is synthesized.

As noted above, in certain embodiments, step e) comprises combining one or more reagents for the deprotection of amino protective groups. For instance, if the amino protective group is an alkoxymethyl or a carbamate, such as a t-butyl carbamate or Fmoc, then the one or more reagents is an acid. In further embodiments, the acid is a mineral acid. Non-limiting examples of mineral acids include hydrochloric acid (HCl), nitric acid (HNO₃), phosphoric acid (H₃PO₄), sulfuric acid (H₂SO₄), boric acid (H₃BO₃), hydrofluoric acid (HF), hydrobromic acid (HBr), and perchloric acid (HClO₄). In some embodiments, the reagent is hydrochloric acid (HCl), nitric acid (HNO₃), phosphoric acid (H₃PO₄), sulfuric acid (H₂SO₄), boric acid (H₃BO₃), hydrofluoric acid (HF), hydrobromic acid (HBr), perchloric acid (HClO₄), or a mixture thereof. In other embodiments, the acid is trifluoroacetic acid (TFA). In another example, if the amino protective group is an alkyl silyl group, the one or more reagents are tetra-n-butylammonium fluoride (TBAF) and/or trifluoroacetic acid (TFA). In yet another example, if the amino protective group is benzyl, then the one or more reagents are Pd/C and H₂.

In yet further embodiments R⁶ is THP (tetrahydropyranyl). In some embodiments, R⁶ is THP and the one or more reagents used to remove the amino protective group is an acid. It has been discovered that non-aqueous acidic reaction conditions help avoid undesirable reactions such as degradation and formation of ring-opening side products. In some embodiments, the acid is generated in situ. In some embodiments, removal of the THP protective group proceeds to completion or near completion in the absence of water. In one embodiment, removal of the THP protective group proceeds to completion or near completion under anhydrous conditions. In another embodiment, removal of the THP protective group proceeds to completion or near completion with less than 0.5% water present. In a further embodiment, the acid is generated in situ. For example, ethanol and acetyl chloride may be used to generate HCl in situ. In some embodiments, step e) comprises an acid selected from the group consisting of a mineral acid, TFA and a Lewis acid. In some embodiments the acid is HCl. In another embodiment, R⁶ is methyl 2-trimethylsilylethyl ether (SEM) and the one or more reagents used to remove the protective group is a fluoride ion.

Deprotection is considered near completion when at least 90%, 95%, 97%, 98%, 99%, 99.5% or 99.9% of the protected material is deprotected.

In some embodiments, step e) is performed at a temperature between 30 and 70 degrees Celsius; between 40 and 60 degrees Celsius; or between 25 and 50 degrees Celsius.

In some embodiments, the compound of formula I or a salt thereof is crystallized from one or more solvents selected from the group comprising water, ethanol, methanol, isopropanol, n-propanol and acetone. In other embodiments, the one or more solvents are i) water; ii) ethanol; iii) acetone; iv) water and ethanol; or v) water, ethanol and acetone.

In some of the foregoing embodiments, the compound of formula 1 is

or a salt thereof.

In some of the foregoing embodiments, the compound of formula 1 is

or a pharmaceutically acceptable salt thereof.

In some of the foregoing embodiments, the compound of formula 1 is

In some of the foregoing embodiments, the compound of formula 2 is

In some of the foregoing embodiments, the compound of formula 3 is

In some of the foregoing embodiments, the compound of formula 4 is

or a salt thereof.

In some of the foregoing embodiments, the compound of formula 4 is

or a pharmaceutically acceptable salt thereof.

In some of the foregoing embodiments, the compound of formula 4 is

In some of the foregoing embodiments, the compound of formula 5 is

or a salt thereof.

In some of the foregoing embodiments, the compound of formula 5 is

or a pharmaceutically acceptable salt thereof.

In some of the foregoing embodiments, the compound of formula 5 is

In some of the foregoing embodiments, the compound of formula 6 is

In some of the foregoing embodiments, the compound of formula 7 is

or a salt thereof.

In some of the foregoing embodiments, the compound of formula 7 is

or a pharmaceutically acceptable salt thereof.

In some of the foregoing embodiments, the compound of formula 7 is

In some of the foregoing embodiments, the compound of formula I is

or a salt thereof.

In some of the foregoing embodiments, the compound of formula I is

or a pharmaceutically acceptable salt thereof.

In some of the foregoing embodiments, the compound of formula I is

The processes described herein provide an efficient synthesis. In addition, the processes reduce or minimize certain process steps and/or side products, such as racemization of chiral centers during deprotection conditions. Furthermore, the processes disclosed herein may be suitable for various purposes, such as one or more of laboratory, industrial, commercial, non-commercial, manufacturing, non-manufacturing, regulatory, non-regulatory, medical, non-medical, pharmaceutical, and experimental uses.

By way of example, the processes of the present application may be suitable for making compounds of the formulas disclosed herein, in the amounts of 1 mg, 5 mg, 10 mg, 50 mg, 100 mg, 250 mg, 500 mg, 750 mg, 1 g, 5 g, 10 g, 50 g, 100 g, 250 g, 500 g, 1 kg, 5 kg, 10 kg, 50 kg, 100 kg, 250 kg, 500 kg, 750 kg, 1000 kg, 2500 kg, and 5000 kg, in a single batch. In addition, the processes of the present application may be suitable for making compounds in the amounts between 1-100 mg, 1-500 mg, 1-1000 mg, 1-100 g, 1-500 g, 1-1000 g, 10-1000 kg, 500-1000 kg, 1000-2000 kg, 1000-5000 kg, and more than 5000 kg in a single batch. Additionally, the processes of the present application may be suitable for making compound in the amounts of at least ling, 100 mg, 1 g, 10 g, 100 g, 1 kg, 10 kg, 100 kg, 1000 kg, 2500 kg, and 5000 kg, in a single batch. Also, the processes described herein may be used for making compounds in single or multiple batches, or in continuous/semi-continuous processes. In some embodiments, the process is a batch process. In some embodiments, the process is a continuous process. In some other embodiments, the process is a semi-continuous process.

By way of example, the processes of the present application may utilize at least about 1 mmol, 10 mmol, 100 mmol, 1 mol, 5 mol, 10 mol, 20 mol, 50 mol, or 100 mol of at least one starting material. The starting material includes any of the starting or intermediate compounds disclosed herein, a salt thereof, or a reagent.

Compounds

In some embodiments, the application discloses the compound of formula 1:

or a salt thereof, wherein R¹ is selected from the group consisting of halo and optionally substituted C₁-C₈ alkyl; R² is selected from the group consisting of H and optionally substituted C₁-C₈ alkyl, and R³ and R⁴ are each independently selected from the group consisting of an amino protective group and an optionally substituted purinyl group. In some embodiments, R¹ is selected from the group consisting of halo and C₁-C₈ alkyl. In some embodiments, R¹ is halo. In some embodiments, R² is selected from the group consisting of H and C₁-C₈ alkyl. In some embodiments, R² is C₁-C₈ alkyl. In some embodiments, R² is C₁-C₄ alkyl. In some embodiments, R¹ is selected from the group consisting of halo and C₁-C₈ alkyl; R² is selected from the group consisting of H and C₁-C₈ alkyl, and R³ and R⁴ are each independently selected from the group consisting of an amino protective group and an optionally substituted purinyl group. In some embodiments, R¹ is halo; R² is C₁-C₈ alkyl, and R³ and R⁴ are each independently selected from the group consisting of an amino protective group and an optionally substituted purinyl group. In some embodiments, R¹ is halo; R² is C₁-C₄ alkyl, and R³ and R⁴ are each independently selected from the group consisting of an amino protective group and an optionally substituted purinyl group. In further embodiments, R³ is an amino protective group and R⁴ is an optionally substituted purinyl group. In further embodiments, R³ and R⁴ are amino protective groups. In further embodiments, R³ is an amino protective group and R⁴ is a purinyl group.

In some embodiments, the application discloses the compound of formula 1:

or a salt thereof; and wherein the compound of formula 1 or a salt thereof is synthesized by a process comprising step a) combining a compound of formula 2:

or a salt thereof, and a compound of formula 3:

wherein the compound of formula 1 or a salt thereof is synthesized, wherein R¹ is halo; R² is selected from the group consisting of H, and optionally substituted C₁-C₈ alkyl; and R³ and R⁴ are each independently selected from the group consisting of an amino protective group and an optionally substituted purinyl group. In other embodiments, R¹, R², R³ and R⁴ are as defined above for the compound of formula 1.

In some embodiments, the application discloses the compound of formula 8:

or a salt thereof, wherein the compound of formula 8 or a salt thereof is synthesized by the process comprising combining a compound of formula 9:

or a salt thereof, and a compound of formula 10:

wherein the compound of formula 8 or a salt thereof is synthesized.

In some embodiments, the application discloses a compound of formula 14:

or a salt thereof, wherein the compound of formula 14 or a salt thereof is synthesized by a process comprising combining a compound of formula 12:

or a salt thereof, and a compound of formula 13:

wherein the compound of formula 14 is synthesized. In further embodiments, the process further comprises combining a compound of formula 11:

or a salt thereof, and an acid, wherein the compound of formula 12 or a salt thereof is synthesized. In some embodiments, the process comprises combining a compound of formula 11:

and an acid, wherein the compound of formula 12 or a salt thereof is synthesized. In yet further embodiments, the process further comprises combining a compound of formula 8:

or a salt thereof, and aniline, wherein the compound of formula 11 is synthesized. In yet another embodiment, the process further comprises combining compound of formula 9:

or a salt thereof, and a compound of formula 10:

wherein the compound of formula 8 or a salt thereof is synthesized.

In some embodiments, the application discloses a compound of formula 15:

or a salt thereof, wherein the compound of formula 15 or a salt thereof is synthesized by a process comprising combining a compound of formula 16:

or a salt thereof, and a compound of formula 10a:

wherein the compound of formula 15 or a salt thereof is synthesized.

In some embodiments, the application discloses a compound of formula 15a:

or a salt thereof, wherein the compound of formula 15a or a salt thereof is synthesized by a process comprising combining a compound of formula 16:

or a salt thereof, wherein BB is halo, and a compound of formula 10a:

wherein AA is an amino protective group and wherein the compound of formula 15 or a salt thereof is synthesized. In some embodiments, BB is F. In some embodiments, the amino protective group is selected from the group consisting of t-butyl carbamate, tetrahydropyranyl, alkylsilyl, benzyl, an optionally substituted purinyl group, and alkoxymethyl. In other embodiments, the amino protective group is carbamate. In some embodiments, the amino protective group is t-butyl carbamate (BOC) or 9-fluoroenylmethyl carbamate (FMOC). In some embodiments, AA is t-butyl carbamate (BOC).

In some embodiments, the application discloses a compound of formula 19:

or a salt thereof, wherein the compound of formula 19 or a salt thereof is synthesized by a process comprising combining a compound of formula 18:

or a salt thereof, and a compound of formula 13:

wherein a compound of formula 19 or a salt thereof is synthesized. In further embodiments, the process further comprises combining a compound of formula 17:

or a salt thereof, and an acid, wherein the compound of formula 18 or a salt thereof is synthesized. In some embodiments, the process further comprises combining a compound of formula 17:

and an acid, wherein the compound of formula 18 or a salt thereof is synthesized. In yet further embodiments, the process further comprises combining a compound of formula 15:

or a salt thereof, and aniline, wherein the compound of formula 17 is synthesized. In yet another embodiment, the process further comprises combining compound of formula 16:

or a salt thereof, and a compound of formula 10:

wherein the compound of formula 15 or a salt thereof is synthesized.

In some embodiments, the application discloses a compound of formula 20:

or a salt thereof, wherein the compound of formula 20 or a salt thereof is synthesized by a process comprising combining a compound of formula 9:

and a compound of formula 10:

wherein the compound of formula 20 or a salt thereof is synthesized. In some embodiments, the process further comprises synthesizing a compound of formula 8:

or a salt thereof. In some embodiments, the compound of formula 8 or a salt thereof ring-opens to form the compound of formula 20 or a salt thereof. In some embodiments, the compound of formula 20 is an intermediate that is formed during the preparation of the compound of formula 8.

A compound of formula 21:

or a salt thereof, wherein the compound of formula 21 or a salt thereof is synthesized by a process comprising combining a compound of formula 16:

or a salt thereof, and a compound of formula 10a:

wherein the compound of formula 21 or a salt thereof is synthesized. In some embodiments, the process further comprises synthesizing a compound of formula 15:

or a salt thereof. In some embodiments, the compound of formula 15 or a salt thereof ring-opens to form the compound of formula 21 or a salt thereof. In some embodiments, the compound of formula 21 is an intermediate that is formed during the preparation of the compound of formula 15.

By way of example, the compositions of the present application may comprise at least 2000 kg, 1000 kg, 750 kg, 500 kg, 250 kg, 100 kg, 10 kg, 1 kg, 0.5 kg, 50 g, 5 g, or 0.5 g of a compound of a formula disclosed herein or a salt thereof. In some embodiments, compositions may comprise a multi-kilogram amount of a compound of a formula disclosed herein or salt thereof. In other embodiments, compositions of the present disclosure may comprise at least about 1 mmol, 10 mmol, 100 mmol, 1 mol, 5 mol, 10 mol, 20 mol, 50 mol, or 100 mol of a compound of a formula disclosed herein or a salt thereof. In addition to a compound of a formula disclosed herein or a salt thereof, composition may further comprise solvents, reagents, or combinations thereof. In another aspect, compositions may consist essentially of a compound of a formula disclosed herein or a salt thereof.

By way of example, the resulting compounds from the processes described herein may be used in a pharmaceutical composition. In another embodiment, provided is a pharmaceutical composition comprising a resulting compound from the processes disclosed herein or a salt thereof, and one or more pharmaceutically acceptable carriers or excipients.

Examples Example 1. Synthesis of a Compound of Formula 17

A compound of formula 16 (1.0 kg, 1.0 eq), a compound of formula 10 (1.5 kg, 1.2 eq) and pyridine (3.0 kg) were added to reactor A. The mixture was agitated at 19 to 25° C. and diphenylphosphite (6.1 kg, 4.0 eq) was added to the mixture over at least 2 h while maintaining the internal temperature at less than about 35° C. The reaction mixture was adjusted to 19 to 25° C. and agitated until the reaction was deemed complete by HPLC analysis (1-3 h). Aniline (0.7 kg, 1.2 eq) was added over a minimum of 1 h while maintaining the internal temperature at less than about 40° C. The reaction mixture was then adjusted to 45 to 55° C. and agitated until the reaction is deemed complete. The reaction mixture was cooled to 19 to 25° C. and toluene (13 kg) was added followed by a prepared 1M HCl solution (10 kg) while maintaining the internal temperature at less than about 30° C. The biphasic mixture was agitated at about 22° C. for at least 30 minutes and then allowed to settle. The aqueous layer was separated and discarded. A second portion of 1M HCl (10 kg) was added to the organic layer in reactor A. The biphasic mixture was agitated at 19 to 25° C. for at least 30 minutes and then allowed to settle. The aqueous layer was separated and discarded. A compound of formula 17 was carried forward to the next step as a stock solution in toluene.

Example 2. Synthesis of a Compound of Formula 18

To the stock solution of a compound of formula 17 in toluene was added acetonitrile (8.4 kg) and concentrated HCl (2.2 kg) while maintaining the internal temperature at no more than 30° C. The reaction mixture was adjusted to 19 to 25° C. and agitated until the reaction was deemed complete. Water (5 kg) was added and the biphasic mixture was agitated at 19 to 25° C. for at least 30 minutes and then allowed to settle. The bottom aqueous layer was separated and transferred to reactor B (product was in the aqueous layer). Water (10 kg) was then added to the organic layer in reactor A. The biphasic mixture was agitated at 19 to 25° C. for at least 30 minutes and then allowed to settle. The bottom aqueous layer was separated and transferred to reactor B (combining with the first aqueous phase). Toluene (4 kg) was added to the combined aqueous layers in reactor B and the biphasic mixture was agitated at 19 to 25° C. for at least 30 minutes and then allowed to settle. The bottom aqueous layer was separated and transferred to reactor A. Toluene (4 kg) was added to reactor A and the biphasic mixture was agitated at 19 to 25° C. for at least 30 minutes and then allowed to settle. The bottom aqueous layer was separated and transferred to reactor B. The aqueous phase was then partially concentrated under vacuum to 18 L to remove toluene and reduce acetonitrile levels to no more than 3.5%. The aqueous phase was then transferred, in portions, to reactor B containing water (5 kg), ammonium hydroxide (6.5 kg, 8.0 eq) and acetonitrile (0.8 kg) while maintaining the internal temperature at no more than 19 to 25° C. The resulting slurry was agitated at 19 to 25° C. for ca 1 h before filtering. The filter cake was rinsed with water (3 kg) and then dried under vacuum at no more than 50° C. to afford 18. ¹H NMR (400 MHz, CDCl₃): δ 7.82 (dd, J=8.4, 2.2 Hz, 1H), 7.71 (dd, J=9.2, 5.0 Hz, 1H), 7.55-7.45 (m, 4H), 7.27 (d, J=6.4 Hz, 2H), 3.69 (q, J=6.4 Hz, 1H), 2.01 (s, 2H), 1.27 (d, J=6.0 Hz, 3H). ¹³C NMR (100 MHz, CDCl₃): δ 162.3, 161.9, 160.5, 159.8, 144.4, 136.6, 130.3, 130.2, 129.9, 129.0, 128.9, 128.4, 123.4, 123.2, 122.3, 122.2, 112.1, 111.9, 48.7, 23.7 (signal splitting due to fluorine results in additional peaks).

Example 3. Synthesis of a Compound of Formula 19

A compound of formula 18 (1.0 kg, 1 eq), a compound of formula 13 (0.9 kg, 1.1 eq), triethylamine (0.5 kg, 1.5 eq), water (4 kg) and EtOH (2 kg) were added to reactor A. The mixture was adjusted to 75 to 85° C. and agitated until the reaction was deemed complete. The mixture was then adjusted to 19 to 25° C. and agitated for ca 1 h before filtering. The isolated compound of formula 19 solid was rinsed with water (2 kg) and heptanes (2×3 kg) and then dried under vacuum. ¹H NMR (400 MHz, CDCl₃): l 8.28 (d, J=2 Hz, 1H), 8.00 (bs, 1H), 7.89 (dd, J=8.8, 3.0 Hz, 1H), 7.73 (m, 1H), 7.59 (m, 3H), 7.48 (m, 2H), 7.35 (m, 1H), 6.68 (m, 1H), 5.69 (dd, J=10.0, 3.0 Hz, 1H), 5.24 (bs, 1H), 4.16 (dd, J=11.6, 2.0 Hz, 1H), 3.77 (tt, J=11.2, 1.4 Hz, 1H), 2.06 (m, 3H), 1.75 (m, 3H), 1.47 (d, J=6.8 Hz, 3H).

Example 4. Synthesis of a Compound of Formula III

To reactor A was added a compound of formula 19 followed by EtOH (4.2 kg). Acetyl chloride (0.33 kg, 1.2 eq) was then added slowly while maintaining the internal temperature at less than about 40° C. The mixture was then adjusted to 19 to 25° C. and agitated until the reaction was deemed complete. After adjusting the temperature to 5 to 15° C., 0.84 kg of a prepared 4.5% sodium carbonate solution was added to the reaction mixture followed by water (1 kg) while maintaining the internal temperature at 5 to 15° C. To reactor B was added 5.44 kg of a prepared 4.5% sodium carbonate solution and the contents were warmed to 65 to 75° C. Approximately 20% of the solution held in reactor A was then transferred to the aqueous solution in reactor B while keeping the internal temperature at 65 to 75° C. The mixture was aged for about 30 minutes until a slurry was formed. The remaining solution from reactor A was transferred to reactor B over a period of about 1 h while maintaining the internal temperature at 65 to 75° C. The slurry was agitated at 65 to 75° C. for 1 to 5 h until a thick slurry was formed. The contents were then adjusted to 19 to 25° C. over about 1 h and agitated about 1 h before filtering. The wet cake was rinsed with water (10 kg) and then dried under vacuum at about 65° C. ¹H NMR (400 MHz, CDCl₃): δ 8.33 (s, 1H), 7.98 (br, 1H), 7.90 (dd, J=8.4, 2.8 Hz, 1H), 7.74 (dd, J=8.8, 5.2 Hz, 1H), 7.65-7.57 (m 3H), 7.51-7.45 (m, 2H), 7.37 (m, 1H), 6.84 (bd, J=8.8 Hz, 1H), 5.27 (br, 1H), 1.75 (br, 1H), 1.50 (d, J=6.8 Hz, 3H). ¹⁹F NMR (400 MHz, CDCl₃): δ −111.11 (referenced to TFA at −76.5 ppm). 

1. A process for synthesizing a compound of formula 1:

or a salt thereof, comprising step a) combining a compound of formula 2:

or a salt thereof, and a compound of formula 3:

wherein the compound of formula 1 or a salt thereof is synthesized, wherein R¹ is halo; R² is selected from the group consisting of H, and optionally substituted C₁-C₈ alkyl; and R³ and R⁴ are each independently selected from the group consisting of hydrogen, an amino protective group and an optionally substituted purinyl group. 2-4. (canceled)
 5. The process of claim 1, wherein step a) further comprises a step of combining a dehydrating agent selected from the group selected from diphenylphosphite, triphenylphosphite, N,N′-dicyclohexylcarbodiimide, N-(3-dimethylaminopropyl)-N′-ethylcarbodiimide hydrochloride, 1,1′-carbonyldiimidazole.
 6. The process of claim 5, wherein step a) further comprises a step of combining a base selected from the group consisting of pyridine, 4-dimethylaminopyridine, triethylamine, isopropylethylamine, imidazole, DABCO, DBU, 2,6-lutidine, and N,N-diisopropylethylamine.
 7. The process of claim 1, wherein step a) further comprises combining a solvent selected from the group consisting of pyridine, toluene, tetrahydrofuran, acetonitrile and 2-MeTHF.
 8. The process of claim 1, wherein step a) is performed at a temperature between 0 and 45 degrees Celsius. 9-23. (canceled)
 24. A process for synthesizing a compound of formula 8:

or a salt thereof, comprising step a) combining a compound of formula 9

or a salt thereof, and a compound of formula 10

wherein the compound of formula 8 or a salt thereof is synthesized. 25-26. (canceled)
 27. The process of claim 24, wherein step a) further comprises a step of combining a dehydrating agent.
 28. The process of claim 27, wherein the dehydrating agent is diphenylphosphite, triphenylphosphite, N,N′-dicyclohexylcarbodiimide, N-(3-dimethylaminopropyl)-N′-ethylcarbodiimide hydrochloride, 1,1′-carbonyldiimidazole.
 29. The process of claim 24, wherein step a) further comprises a base selected from the group consisting of pyridine, 4-dimethylaminopyridine, triethylamine, isopropylethylamine, imidazole, DABCO, DBU, 2,6-lutidine, and N,N-diisopropylethylamine.
 30. The process of claim 24, wherein step a) further comprises a solvent selected from the group consisting of pyridine, toluene, tetrahydrofuran, acetonitrile and 2-MeTHF.
 31. The process of claim 24, wherein step a) is performed at a temperature between 0 and 45 degrees Celsius. 32-46. (canceled)
 47. A process for synthesizing a compound of formula 15:

or a salt thereof, comprising step a) combining a compound of formula 16:

or a salt thereof, and a compound of formula 10a:

wherein the compound of formula 15 or a salt thereof is synthesized. 48-49. (canceled)
 50. The process claim 47, wherein step a) further comprises a step of combining a dehydrating agent.
 51. The process of claim 50, wherein the dehydrating agent is diphenylphosphite, triphenylphosphite, N,N′-dicyclohexylcarbodiimide, N-(3-dimethylaminopropyl)-N′-ethylcarbodiimide hydrochloride, 1,1′-carbonyldiimidazole.
 52. The process of claim 47, wherein step a) further comprises a step of combining a base selected from the group consisting of pyridine, 4-dimethylaminopyridine, triethylamine, isopropylethylamine, imidazole, DABCO, DBU, 2,6-lutidine, and N,N-diisopropylethylamine.
 53. The process of claim 47, wherein step a) further comprises combining a solvent selected from the group consisting of pyridine, toluene, tetrahydrofuran, acetonitrile and 2-MeTHF.
 54. The process of claim 47, wherein step a) is performed at a temperature between 0 and 45 degrees Celsius. 55-69. (canceled)
 70. A compound of formula 8:

or a salt thereof.
 71. A compound of formula 15:

or a salt thereof. 72-73. (canceled)
 74. A compound of formula 20:

or a salt thereof.
 75. A compound of formula 21:

or a salt thereof. 